This invention relates to supported transition metal complexes formed from vinyl- or poly(vinyl)-functionalized supports that are useful as addition polymerization catalysts, especially as catalysts for polymerization of olefins. More particularly, the invention relates to readily formable supported catalysts comprising a metal complex that is chemically bound or tethered to the support through a non-fugitive ligand group. The invention also relates to the preparation of such supported compositions, to their use in an olefin polymerization process, and to certain functionalized supports particularly adapted to this use.
Numerous supported catalysts for use in addition polymerizations have been previously disclosed in the art. WO-91/09882 described a supported catalyst prepared by combining i) a bis(cyclopentadienyl) metal compound containing at least one ligand capable of reacting with a proton, ii) an activator component comprising a cation capable of donating a proton and a bulky, labile anion capable of stabilizing the metal cation formed as a result of reaction between the metal compound and the activator component, and iii) a catalyst support material. Similarly, WO-94/03506 described a supported ionic catalyst prepared by combining i) a monocyclopentadienyl metal compound, ii) a cationic activator component, and iii) a catalyst support material. Optionally, the supported ionic catalyst could be prepolymerized with an olefinic monomer. The support material could also be treated with a hydrolyzable organoadditive, preferably a Group 13 alkyl compound such as triethylaluminum. Such supported catalysts do not provide for chemically attaching any of the catalyst components to the support material, and accordingly, are unsuited for use in slurry polymerizations or other reactions where solvents or diluents are present which can remove catalysts from the support.
In U.S. Pat. No. 5,427,991, certain catalyst supports comprising polyanionic moieties constituted of noncoordinating anionic groups chemically bonded to crosslinked polymeric core components were disclosed. It is also well known to attach or bind alumoxanes to inert supports. Disadvantageously, binding of the cocatalyst to the support results in catalyst compositions having low productivity, likely due to inferior activation ability or activity of immobilized cocatalysts.
Supported metallocene catalysts wherein one or more delocalized moieties of the metallocene are chemically attached to polymeric organic or particulated inorganic materials, including silica, are known from U.S. Pat. Nos. 5,399,636, 5,587,439, 6,040,261, WO98/09913 and WO98/03521. Disadvantageously, preparing and using solid functionalized reagents for synthesis of metallocenes and similar organometal compounds using organometallic synthetic processes is prohibitively expensive and unsuited for use on an industrial scale. Moreover, such processes utilizing condensation reactions to tether a catalyst component also generate one or more by-products that can interfere with subsequent polymerizations. Moreover, similar chemistries based on diimine and/or diimine functionalized supports used to synthesize donor complexes with Group 3-10 metal compounds result in catalysts having inferior catalytic properties, due it is believed, to the presence of Lewis base functionality in close proximity to the metal catalyst center.
In US 2002/0082161, certain functionalized particulated supports containing diene or alkyne groups formed by reaction of trialkylaluminum treated silica with the corresponding diene or alkyne functionalized alcohols were disclosed. The compositions were used for preparing supported olefin polymerization catalysts by reaction with metal complexes containing substituents that were, “capable of reaction with the diene or alkyne functionality of the support”. Examples included Group 3-10 metallocene and constrained geometry complexes having replaceable ligands. Disadvantageously, when the functionalized support comprises one of the donor ligands in the active catalyst, interference with the electronic environment of the metal cation or other catalytic species can occur. Moreover, if the tether is a single bond to the metal catalyst center, displacement of the solid phase ligand by an olefin during polymerization can destroy the tether, resulting in leaching of the catalyst and/or loss of catalyst activity in the presence of liquids, especially slurry diluents.
Certain resin bound 4-substituted 2-aminobutadiene supports prepared through a Wittig reaction with polymer supported 2-(N-piperazino)propyl-1-enyl-1-triphenylphosphonium bromide were disclosed in Tetrahedron. Letters, 38 (40), 7111-7114 (1997). The compositions were stated to be useful as resin bound dienes for solid phase [4+2]cycloaddition reactions.
The ability of certain polyvalent amine complexes of Group 4 metals to form ortho-metallated derivatives via in situ ligand exchange with adjacent aromatic-, particularly naphthalenyl-, functionality has been disclosed previously in US-A-2004/0220050. Additional references related generally to metal complexes based on polyvalent metal-centered, heteroaryl donor ligands include U.S. Pat. Nos. 6,103,657, 6,320,005, 6,653,417, 6,637,660, 6,906,160, 6,919,407, 6,927,256, 6,953,764, US-A-2002/0142912, US-A-2004/0220050, US-A-2004/0005984, EP-A-874,005, EP-A-791,609, WO 2000/20377, WO 2001/30860, WO 2001/46201, WO 2002/24331, WO 2002/38628, WO 2003/040195, WO 2004/94487, WO 2006/20624, and WO 2006/36748.
It would be desirable to provide a supported olefin polymerization catalyst and a polymerization process using the same that is capable of producing olefin polymers at good catalyst efficiencies in which the metal complex is covalently bound to the support, especially a particulated inorganic material. It would further be desirable to provide such a supported catalyst composition that is devoid of Lewis base groups adjacent to or attached to the metal center and that is adapted for use in a slurry and/or gas phase polymerization process while being relatively unaffected by the presence of condensed monomer and/or diluents. Finally, it would be desirable if there were provided a method for forming tethered, supported metal complexes from Group 4 metal complexes that do not entail preparation of solid compounds containing delocalized π-bound ligand groups or the use of condensation reactions of solid reagents in the synthesis.